John R Brockenbrough

US Patent:

7718918, May 18, 2010

Filed:

Oct 7, 2008

Appl. No.:

12/246820

Inventors:

Donald J. Spinella - Greensburg PA, US
John R. Brockenbrough - Murrysville PA, US
Joseph M. Fridy - Pittsburgh PA, US

Assignee:

Alcoa Inc - Alcoa Center PA

International Classification:

B23K 11/24

US Classification:

219110, 219 868, 219 8651, 219 861

Abstract:

A production line method of resistance welding comprising the steps of contacting a metal sheet with an electrode having an initial contact surface area at a force to provide a pressure to the metal sheet; applying a current though the electrode to the metal sheet; measuring dimensional changes of the electrode; correlating dimensional changes in the electrode to changes in the initial contact surface area; and adjusting the force to compensate for the changes in the initial contact surface area of the electrode to maintain pressure to the metal sheet. The force may be adjusted by stepping the force to maintain pressure to the faying surface of the metal sheet to be welded. By maintaining the pressure at the faying surface the life cycle of the electrodes may be increased without forming discrepant welds.

US Patent:

20070131655, Jun 14, 2007

Filed:

Dec 9, 2005

Appl. No.:

11/298216

Inventors:

Donald Spinella - Greensburg PA, US
John Brockenbrough - Murrysville PA, US
Joseph Fridy - Pittsburgh PA, US

International Classification:

B23K 31/02
B23K 20/00
B23K 31/12

US Classification:

219061400, 219061500, 228102000, 228103000

Abstract:

The present invention provides an improved method of resistance welding comprising the steps of contacting a metal sheet with an electrode having an initial contact surface area at a force to provide a pressure to the metal sheet; applying a current through the electrode to the metal sheet; measuring dimensional changes of the electrode; correlating dimensional changes in the electrode to changes in the initial contact surface area; and adjusting the force to compensate for the changes in the initial contact surface area of the electrode to maintain pressure to the metal sheet. The force may be adjusted by stepping the force to maintain pressure to the faying surface of the metal sheet to be welded. By maintaining the pressure at the faying surface the life cycle of the electrodes may be increased without forming discrepant welds. The current may also be stepped to further extend electrode life.